Why Do You Need to Charge your Hydraulic Accumulators?

Blog | October 25th, 2017

Hydraulic accumulators store circuit energy. Inside this relatively simple device, that energy is stored in a fluid or a spring. Purely mechanical models use that ‘charge’ to transfer energy to a piston. As for the gas-charged models, well, they transfer the energy from the incompressible hydraulic medium, via a bladder, to a compressible fluid. Definitions like these are easy enough to pull off, but unique system features require a little more thought.

Hydraulic Accumulators: Pre-charge Importance 

Classed as active hydraulic circuit components, the pre-charge cycle keeps one side of the device primed so that it can instantaneously withstand the shock produced by any changes in the system. Additionally, the accumulator is designed to smooth pump pulsing events, so this cushioning section should hold a charge at all times, as it acts very much like a mechanical dampening element. In the case of the diaphragm or bladder equipped hydraulic accumulators on the market, dry nitrogen, an inert gas, is employed as the charge agent. Energized in this manner, the sealed vessel is prepped for the slightest transient system spike and ready for action as a process dampener.

Installation Precautions 

Shipped discharged or with a slight nitrogen charge, the initial nitrogen load is applied during the installation stage. There’s usually a charge gland on the device, plus a bleed valve. Before the hydraulic component enters service, it must be charged according to the loading parameters that came with the product. If this spec sheet is missing, find the charge rating online at the manufacturer’s page. If the device isn’t kept charged, the bladder or piston assembly inside the vessel section will likely incur damage, with the undampened section losing all resistance until it slams into the gas end cap. Additionally, just like a charged electrical capacitor, all due caution must be taken when maintaining this device, as some charge may remain locked inside the gas section. Prior to working on a hydraulic accumulator, connect a pressure gauge and bleed the pressure until the device is safe to be worked upon.

Like an active spring, a gas-energized vessel, hydraulic accumulators retain their charge so that they’re instantly prepared for any change in the fluid characteristics inside that system. Pre-charged in this way, the unit delivers instant performance to the fluid-powered mechanical parts while also acting as a dampening aid. Take care, though, for at least two sections exist inside that chamber. The hydraulic section works independently from the gas-charged section, so both halves must be discharged before the component is deemed safe to work upon.

Mobile Hydraulic Specialties Pty Ltd

Factory 89, 38-40 Popes Road
Keysborough, Victoria, 3173

Phone: (03) 9798-6511

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